Thu·Nov 30, 2017Thursday·November 30, 2017

1. 01*

   Top partner-resonance interplay in a composite Higgs framework

   Juan Yepes🇨🇱 · Alfonso Zerwekh🇨🇱

   Guided us by the scenario of weak scale naturalness and the possible existence of exotic resonances, we have explored in a $SO(5)$ Composite Higgs set-up the interplay among three matter sectors: elementary, top partners and vector resonances. We parametrise it through explicit interactions of spin-1 $SO(4)$-resonances, coupled to the $SO(5)$-invariant fermionic currents and tensors presented in this work. Such invariants are built upon the Standard Model fermion sector as well as top partners sourced by the unbroken $SO(4)$. The mass scales entailed by the top partner and vector resonance sectors will control the low energy effects emerging from our interplaying model. Its phenomenological impact and parameter spaces have been considered via flavour-dijet processes and electric dipole moments bounds. Finally, the strength of the Nambu-Goldstone symmetry breaking and the extra couplings implied by the top partner mass scales are measured in accordance with expected estimations.

   hep-phInt.J.Mod.Phys.A(2018)·11 citations
2. 02*

   Higgs-Inflaton Mixing and Vacuum Stability

   Yohei Ema🇯🇵 · Mindaugas Karciauskas🇫🇮 · Oleg Lebedev🇫🇮 · Stanislav Rusak🇸🇪 · Marco Zatta🇫🇮

   The quartic and trilinear Higgs field couplings to an additional real scalar are renormalizable, gauge and Lorentz invariant. Thus, on general grounds, one expects such couplings between the Higgs and an inflaton in quantum field theory. In particular, the (often omitted) trilinear coupling is motivated by the need for reheating the Universe after inflation, whereby the inflaton decays into the Standard Model (SM) particles. Such a coupling necessarily leads to the Higgs-inflaton mixing, which could stabilize the electroweak vacuum by increasing the Higgs self-coupling. We find that the inflationary constraints on the trilinear coupling are weak such that the Higgs-inflaton mixing up to order one is allowed, making it accessible to colliders. This entails an exciting possibility of a direct inflaton search at the LHC.

   hep-phastro-ph.COPLB(2019)·41 citations
3. 03*

   Molecular ${\Omega }_b$ states

   Wei-Hong Liang🇨🇳 · J. M. Dias🇪🇸 · V. R. Debastiani🇪🇸 · E. Oset🇪🇸

   Motivated by the recent finding of five ${\Omega }_c$ states by the LHCb collaboration, and the successful reproduction of three of them in a recent approach searching for molecular states of meson-baryon with the quantum numbers of ${\Omega }_c$, we extend these ideas and make predictions for the interaction of meson-baryon in the beauty sector, searching for poles in the scattering matrix that correspond to physical states. We find several ${\Omega }_b$ states: two states with masses 6405~MeV and 6465~MeV for $J^P={\frac{1}{2}}^{-}$; two more states with masses 6427~MeV and 6665~MeV for ${\frac{3}{2}}^{-}$; and three states between 6500 and 6820~MeV, degenerate with $J^P={\frac{1}{2}}^{-},{\frac{3}{2}}^{-}$, stemming from the interaction of vector-baryon in the beauty sector.

   hep-phnucl-thNPB(2018)·36 citations
4. 04*

   Multiquark States

   Marek Karliner🇮🇱 · Jonathan L. Rosner🇺🇸 · Tomasz Skwarnicki🇺🇸

   Why do we see certain types of strongly interacting elementary particles and not others? This question was posed over 50 years ago in the context of the quark model. M. Gell-Mann and G. Zweig proposed that the known mesons were $q\bar{q}$ and baryons $qqq$, with quarks known at the time $u$ ("up"), $d$ ("down"), and $s$ ("strange") having charges (2/3,-1/3,-1/3). Mesons and baryons would then have integral charges. Mesons such as $qq\bar{q}\bar{q}$ and baryons such as $qqqq\bar{q}$ would also have integral charges. Why weren't they seen? They have now been seen, but only with additional heavy quarks and under conditions which tell us a lot about the strong interactions and how they manifest themselves. The present article describes recent progress in our understanding of such "exotic" mesons and baryons.

   hep-phAnn.Rev.Nucl.Part.Sci.(2018)·309 citations
5. 05*

   Dirac neutrinos, dark matter stability and flavour predictions from Lepton Quarticity

   Salvador Centelles Chuliá🇪🇸

   We propose to relate dark matter stability to the possible Dirac nature of neutrinos. The idea is illustrated in a simple scheme where small Dirac neutrino masses arise from a type-I seesaw mechanism as a result of a $Z_4$ discrete lepton number symmetry. The latter implies the existence of a viable WIMP dark matter candidate, whose stability arises from the same symmetry which ensures the Diracness of neutrinos. The symmetry groups ${\Delta }_{27}$ and $A_4$ are then used to extract a rich variety of flavour predictions.

   hep-phhep-ex7 citations
6. 06*

   The nature of the $X(3915)/X(3930)$ resonances from a coupled-channels approach

   Pablo G. Ortega🇪🇸 · Jorge Segovia🇪🇸

   The positive parity ${\chi }_{cJ}(2P)$ charmonium states are expected to lie around the 3.9 GeV/$c^2$ energy region, according to the predictions of quark models. However, a plethora of states with difficult assignment and unconventional properties have been discovered over the years, i.e., the $X(3872)$, $X(3940)$, $Y(3940)$, $X(3915)$, $X(3860)$ and the $X(3930)$ resonances, which complicates the description of this intriguing region. In this work we analyze the $0^{++}$ and $2^{++}$ sectors, employing a coupled-channels formalism successfully applied to the $1^{++}$ sector, where the $X(3872)$ was described as a $D{\bar{D}}^{\ast }+h.c.$ molecule with a sizable $c\bar{c}$ $(2^3{P}_1)$ component. This coupled-channels formalism is based on a widely-used Constituent Quark Model, which describes the quark-quark interactions, and the ${}^3{P}_0$ quark pair creation mechanism, used to couple the two and four quark sectors. The recent controversy about the quantum numbers of the $X(3915)$ state, the properties of the $X(3930)$ one and the nature of the new $X(3860)$ resonance are analyzed in a unified theoretical framework, being all the parameters completely constrained from previous calculations in the low-lying heavy quarkonium phenomenology.

   hep-phPoS(2018)·0 citations
7. 07*

   Analysis of the ${\frac{3}{2}}^{\pm }$ pentaquark states in the diquark model with QCD sum rules

   Jun-Xia Zhang🇨🇳 · Zhi-Gang Wang🇨🇳 · Zun-Yan Di🇨🇳

   In this article, we construct the scalar-diquark-axialvector-diquark-antiquark type interpolating currents, and study the masses and pole residues of the $J^P={\frac{3}{2}}^{\pm }$ hidden-charmed pentaquark states with the QCD sum rules. In calculations, we use the formula $\mu =\sqrt{M_P^2-(2{\mathbb{M}}_c{)}^2}$ to determine the energy scales of the QCD spectral densities. We obtain the masses of the hidden-charm pentaquark states with the strangeness $S=-1$ and $S=-2$, which can be confronted to the experimental data in the future.

   hep-phActa Phys.Polon.B(2017)·22 citations
8. 08*

   The extended BLMSSM with a 125 GeV Higgs boson and dark matter

   Shu-Min Zhao🇨🇳 · Tai-Fu Feng🇨🇳 · Guo-Zhu Ning🇨🇳 · Jian-Bin Chen🇨🇳 · Hai-Bin Zhang🇨🇳 · Xing Xing Dong🇨🇳

   To extend the BLMSSM, we not only add exotic Higgs superfields $({\Phi }_{NL},{\phi }_{NL})$ to make the exotic lepton heavy, but also introduce the superfields($Y$,$Y^{\prime }$) having couplings with lepton and exotic lepton at tree level. The obtained model is called as EBLMSSM, which has difference from BLMSSM especially for the exotic slepton(lepton) and exotic sneutrino(neutrino). We deduce the mass matrices and the needed couplings in this model. To confine the parameter space, the Higgs boson mass $m_{h^0}$ and the processes $h^0\to \gamma \gamma$, $h^0\to VV,V=(Z,W)$ are studied in the EBLMSSM. With the assumed parameter space, we obtain reasonable numerical results according to data on Higgs from ATLAS and CMS. As a cold dark mater candidate, the relic density for the lightest mass eigenstate of $Y$ and $Y^{\prime }$ mixing is also studied.

   hep-phEPJC(2018)·7 citations
9. 09*

   Diquark-diquark-antiquark model for pentaquarks with hidden charm: current status and problems

   V.V. Anisovich🇷🇺 · M.A. Matveev🇷🇺 · J. Nyiri🇭🇺 · A.V. Sarantsev🇷🇺 · A.N. Semenova🇷🇺

   The $J/\psi p$ signals at 4380 MeV and 4450 MeV which were seen by the LHCb collaboration in the decay ${\Lambda }_b^0\to K^{-}J/\psi p$ are discussed following the hypothesis of the existence of diquark-diquark-antiquark composite states. The discussed problems concern: (i) estimation of masses and mass splittings for low-lying states, (ii) determination of decay modes in the quark recombination scheme, (iii) unitarity and analyticity constrains for pentaquark propagators, (iv) hadronic deuteron-like components in the diquark-diquark-antiquark multiplet.

   hep-ph2 citations
10. 10*

    Ponderomotive effects in multiphoton pair production

    Christian Kohlfürst🇩🇪 · Reinhard Alkofer🇦🇹

    The Dirac-Heisenberg-Wigner formalism is employed to investigate electron-positron pair production in cylindrically symmetric but otherwise spatially inhomogeneous, oscillating electric fields. The oscillation frequencies are hereby tuned to obtain multiphoton pair production in the nonperturbative threshold regime. An effective mass as well as a trajectory-based semi-classical analysis are introduced in order to interpret the numerical results for the distribution functions as well as for the particle yields and spectra. The results, including the asymptotic particle spectra, display clear signatures of ponderomotive forces.

    hep-phquant-phPRD(2018)·51 citations
11. 11*

    $R(K^{(\ast )})$ from dark matter exchange

    James M. Cline🇨🇦 · Jonathan M. Cornell🇨🇦

    Hints of lepton flavor violation have been observed by LHCb in the rate of the decay $B\to K{\mu }^{+}{\mu }^{-}$ relative to that of $B\to K{e}^{+}{e}^{-}$. This can be explained by new scalars and fermions which couple to standard model particles and contribute to these processes at loop level. We explore a simple model of this kind, in which one of the new fermions is a dark matter candidate, while the other is a heavy vector-like quark and the scalar is an inert Higgs doublet. We explore the constraints on this model from flavor observables, dark matter direct detection, and LHC run II searches, and find that, while currently viable, this scenario will be directly tested by future results from all three probes.

    hep-phPLB(2018)·39 citations
12. 12*

    Search for Double Charged Particles as Direct Test for Dark Atom Constituents

    O. V. Bulekov🇷🇺 · M. Yu. Khlopov🇷🇺 · A. S. Romaniouk🇷🇺 · Yu. S. Smirnov🇷🇺

    The nonbaryonic dark matter of the Universe is assumed to consist of new stable particles. Stable particle candidates for cosmological dark matter are usually considered as neutral and weakly interacting. However stable charged leptons and quarks can also exist hidden in elusive dark atoms and can play a role of dark matter. Such possibility is strongly restricted by the constraints on anomalous isotopes of light elements that form positively charged heavy species with ordinary electrons. This problem might be avoided, if stable particles with charge -2 exist and there are no stable particles with charges +1 and -1. These conditions cannot be realized in supersymmetric models, but can be satisfied in several alternative scenarios, which are discussed in this paper. The excessive -2 charged particles are bound with primordial helium in O-helium atoms, maintaining specific nuclear-interacting form of the dark matter. O-helium dark matter can provide solution for the puzzles of dark matter searches. The successful development of composite dark matter scenarios appeals to experimental search for doubly charged constituents of dark atoms. Estimates of production cross section of such particles at LHC are presented and discussed. Signatures of double charged particles in the ATLAS experiment are outlined.

    hep-phastro-ph.HEhep-exBled Workshops Phys.(2017)·9 citations
13. 13*

    Overlap between Lattice QCD and HRG with in-medium effects and parity doubling

    Kenji Morita🇯🇵 · Chihiro Sasaki🇵🇱 · Pok Man Lo🇵🇱 · Krzysztof Redlich🇵🇱

    We investigate the fluctuations and correlations involving baryon number in hot hadronic matter with modified masses of negative-parity baryons, in the context of the hadron resonance gas. Temperature-dependent masses are adopted from the recent lattice QCD results and from a chiral effective model which implements the parity doubling structure with respect to the chiral symmetry. Confronting the baryon number susceptibility, baryon-charge correlation, and baryon-strangeness correlation and their ratios with the lattice QCD data, we show that the strong downward mass shift in hyperons can accidentally reproduce some correlation ratios, however it also tends to overshoot the individual fluctuations and correlations. This indicates, that in order to correctly account for the influence of the chiral symmetry restoration on the fluctuation observables, a consistent framework of in-medium effects beyond hadron mass shifts is required.

    hep-phhep-latnucl-thEPJ Web Conf.(2018)·4 citations
14. 14*

    Discrete Flavour Symmetries, Neutrino Mixing and Leptonic CP Violation

    S. T. Petcov🇮🇹

    The current status of our knowledge of the 3-neutrino mixing parameters and of the CP violation in the lepton sector is summarised. The discrete symmetry approach to understanding the observed pattern of neutrino mixing and the related predictions for neutrino mixing angles and leptonic Dirac CP violation are reviewed.

    hep-phEPJC(2018)·190 citations
15. 15*

    Pole structure and compositeness

    J.A. Oller🇪🇸

    We present in this talk a series of new results on the nature of a bound state or resonance based on the calculation of the expectation values of the number operators of the free particles in the state of interest. In this way, a new universal criterion for the elementariness of a bound state emerges. In the case of large particle wavelengths compared to the range of their interaction, a new closed formula for the compositeness of a bound state in a two-particle continuum is obtained. The extension of these results to resonances with respect to the open channels can be given by making use in addition of suitable phase-factor transformations as also reviewed here. We end with a discussion on the $X(3872)$ as possible double- or triple-pole virtual state, which would be the first case in particle phenomenology.

    hep-phhep-thnucl-thPoS(2018)·1 citation
16. 16*

    Quantum and Classical Dynamics of Heavy Quarks in a Quark-Gluon Plasma

    Jean-Paul Blaizot🇫🇷 · Miguel Angel Escobedo🇫🇮

    We derive equations for the time evolution of the reduced density matrix of a collection of heavy quarks and antiquarks immersed in a quark gluon plasma. These equations, in their original form, rely on two approximations: the weak coupling between the heavy quarks and the plasma, the fast response of the plasma to the perturbation caused by the heavy quarks. An additional semi-classical approximation is performed. This allows us to recover results previously obtained for the abelian plasma using the influence functional formalism. In the case of QCD, specific features of the color dynamics make the implementation of the semi-classical approximation more involved. We explore two approximate strategies to solve numerically the resulting equations in the case of a quark-antiquark pair. One involves Langevin equations with additional random color forces, the other treats the transition between the singlet and octet color configurations as collisions in a Boltzmann equation which can be solved with Monte Carlo techniques.

    hep-phnucl-thJHEP(2018)·129 citations
17. 17*

    The invariant and helicity amplitudes in the transitions ${\Lambda }_b\to {\Lambda }^{\ast }({\frac{1}{2}}^{\pm },{\frac{3}{2}}^{\pm })+J/\psi$

    Mikhail A. Ivanov🇷🇺

    We present results for the invariant and helicity amplitudes in the transitions ${\Lambda }_b\to {\Lambda }^{(\ast )}(J^P)+J/\psi$ where the ${\Lambda }^{(\ast )}(J^P)$ are $\Lambda (sud)$-type ground and excited states with $J^P$ quantum numbers $J^P={\frac{1}{2}}^{\pm },{\frac{3}{2}}^{\pm }$. The calculations are performed in the framework of a covariant confined quark model. This analysis is important for the identification of the hidden charm pentaquark states $P_c^{+}(4380)$ and $P_c^{+}(4450)$ which were discovered by the LHCb Coll. We also discuss the possible New Physics effects in the exclusive decays ${\bar{B}}^0\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$. We extend the Standard Model by taking into account right-handed vector (axial), left- and right-handed (pseudo)scalar, and tensor current contributions. The ${\bar{B}}^0\to D^{(\ast )}$ transition form factors are calculated in the full kinematic $q^2$ range by employing a covariant quark model.

    hep-phhep-exPoS(2017)·0 citations
18. 18*

    First results from an extended freed-isobar analysis at COMPASS

    Fabian Krinner (for the COMPASS collaboration)🇩🇪

    One of the goals of the COMPASS experiment is the precision study of light-meson spectroscopy with data for various final states. With $46\times 10^6$ exclusive events, the process ${\pi }^{-}p\to {\pi }^{-}{\pi }^{+}{\pi }^{-}p$ constitutes the flagship channel. Based on this data set, the results of an extensive partial-wave analysis (PWA), using a total of 88 partial waves in the model, were published. Along with it, results of a first study of the so-called freed-isobar method were shown. Here, the fixed amplitudes for appearing ${\pi }^{+}{\pi }^{-}$ intermediate states used in the conventional analysis were replaced by sets of piecewise constant functions to extract the amplitudes of the ${\pi }^{+}{\pi }^{-}$ subsystems directly from the data. In this first study, this was one for three $\pi$ partial waves with $J^{PC}=0^{++}$ intermediate ${\pi }^{+}{\pi }^{-}$ states. The promising results inspired further extension of this method, by also freeing intermediate ${\pi }^{+}{\pi }^{-}$ states with $J^{PC}=1^{--}$ and $2^{++}$. With this extension of the set of freed waves, mathematical ambiguities in the model arise due to the much higher flexibility of the model. We will present first results of these extended studies on COMPASS data along with methods to resolve the arising ambiguities.

    hep-phhep-exPoS(2018)·2 citations
19. 19*

    Production of neutral Higgs bosons associated with Z-boson and photon in 2HDM at future lepton colliders

    Nasuf Sonmez🇹🇷

    Inspired by precision tests of the Standard Model in future lepton colliders, the numerical analysis of the following scattering processes, $e^{+}{e}^{-}\to Z{h}^0\gamma$ and $e^{+}{e}^{-}\to Z{H}^0\gamma$, are carried at the tree level including all possible diagrams in the two-Higgs-doublet model (2HDM). This model has many free parameters, but the parameters which take part in the scattering amplitudes of these two processes are primarily the mixing angle parameter, $s_{\beta -\alpha }$, and the masses of the neutral Higgs bosons, ($h^0,H^0$). Therefore, measuring the production rates of $Z{h}^0\gamma$ and $Z{H}^0\gamma$ final states open another test for the scalar sectors of the 2HDM. The numerical analysis is performed under the current experimental constraints. The production rates and the asymmetry in the forward-backward direction are presented as a function of the center-of-mass energy covering the future lepton colliders. The unpolarized cross-section gets up to 6.19 (4.86) fb at $\sqrt{s}=350$ (500) GeV and 0.164 (0.157) fb at $\sqrt{s}=350$ (500) GeV for $e^{+}{e}^{-}\to Z{h}^0\gamma$ and $e^{+}{e}^{-}\to Z{H}^0\gamma$, respectively. The polarization of the incoming $e^{+}{e}^{-}$ beams are studied for various configurations, and it enhances the cross-section by a factor of 1.78 in both processes for $P_{e^{+},e^{-}}=(+0.6,-0.8)$.

    hep-ph0 citations
20. 20*

    Machine learning challenges in theoretical HEP

    Stefano Carrazza🇨🇭

    In these proceedings we perform a brief review of machine learning (ML) applications in theoretical High Energy Physics (HEP-TH). We start the discussion by defining and then classifying machine learning tasks in theoretical HEP. We then discuss some of the most popular and recent published approaches with focus on a relevant case study topic: the determination of parton distribution functions (PDFs) and related tools. Finally, we provide an outlook about future applications and developments due to the synergy between ML and HEP-TH.

    hep-phJ.Phys.Conf.Ser.(2018)·6 citations
21. 21*

    The Born approximation for bound states

    Paul Hoyer🇫🇮

    Bound states are stationary in time and interact continuously. Even a first approximation of atomic wave functions in QED requires contributions of all orders in \alpha. Bound state perturbation theory depends on the choice of this first approximation, just as the Taylor expansion of an ordinary function depends on the expansion point. Considering the expansion to be not in $\alpha$ but in $\hslash$, i.e., in the number of loops, defines the perturbative expansion uniquely also for bound states. I show how the Schrödinger equation for Positronium with the classical potential $V(r)=-\alpha /r$ corresponds to the Born, $O({\hslash }^0)$ bound state approximation in QED. Standard perturbation theory is based on an expansion around $O({\alpha }^0)$ free states that have no overlap with bound states. Perturbing around bound states requires using interacting $in$ and $out$ states. For Born states the binding potential arises from a classical gauge field. In the absence of loops the QCD scale ${\Lambda }_{QCD}$ can originate from a boundary condition imposed on the solution of the classical gluon field equations. A perturbative expansion may be relevant even for hadrons, if their non-perturbative features such as confinement and chiral symmetry breaking are present already in the Born term.

    hep-phPoS(2018)·0 citations
22. 22*

    Phase diagram and isentropic curves from the vector meson extended Polyakov quark meson model

    Péter Kovács🇭🇺 · György Wolf🇭🇺

    In the framework of the $N_f=2+1$ flavor (axial)vector meson extended Polyakov quark meson model we investigate the QCD phase diagram at finite temperature and density. We use a ${\chi }^2$ minimization procedure to parameterize the model based on tree\,-\,level decay widths and vacuum scalar and pseudoscalar curvature masses which incorporate the contribution of the constituent quarks. Using a hybrid approximation (mesons at tree level, fermions at one\,-\,loop level) for the grand potential we determine the phase boundary both on the ${\mu }_B-T$ and $\rho -T$ planes. We also determine the location of the critical end point of the phase diagram. Moreover by calculating the pressure and other thermodynamical quantities derived from it, we determine a set of isentropic curves in the crossover region. We show that the curves behave very similarly as their counterparts obtained from the lattice in the crossover regime.

    hep-phActa Phys.Polon.Supp.(2017)·7 citations
23. 23*

    The phase diagram in the vector meson extended linear sigma model

    Gy. Wolf🇭🇺 · P. Kovács🇭🇺

    We investigate the chiral phase transition of the strongly interacting matter at nonzero temperature and baryon chemical potential ${\mu }_B$ within an extended (2+1) flavor Polyakov constituent quark-meson model which incorporates the effect of the vector and axial vector mesons. The parameters of the model are determined by comparing masses and tree-level decay widths with experimental values. We examine the restoration of the chiral symmetry by monitoring the temperature evolution of condensates. We study the $T-{\rho }_B$ phase diagram of the model and find that a critical end point exists, although at very low density.

    hep-phActa Phys.Polon.Supp.(2017)·0 citations
24. 24*

    Model independent investigation of rare semileptonic b \to u l \bar{\nu}_l decay processes

    Suchismita Sahoo🇮🇳 · Atasi Ray🇮🇳 · Rukmani Mohanta🇮🇳

    Motivated by the recent observation of lepton universality violation in the flavour changing charged current transitions $b\to cl{\bar{\nu }}_l$, we intend to scrutinize the lepton non-universality effects in rare semileptonic $B$ meson decays involving the quark level transitions $b\to ul{\bar{\nu }}_l$. In this regard, we envisage the model-independent approach and consider the generalized effective Lagrangian in the presence of new physics and constrain the new parameters by using the experimental branching fractions of $B_u^{+}\to l^{+}{\nu }_l$ and $B^{-}\to {\pi }^0{\mu }^{-}{\bar{\nu }}_{\mu }$ processes, where $l=e,\mu ,\tau$. We then estimate the branching ratios and forward-backward asymmetries of $B_{(s)}\to P(V)l{\bar{\nu }}_l$ processes, where $P(=K,\pi ,{\eta }^{(\prime )})$ denotes the pseudoscalar meson and $V(=K^{\ast },\rho )$ is the vector meson. We also find out various lepton non-universality parameters in these processes in the presence of new physics.

    hep-phPRD(2017)·9 citations
25. 25*

    Three-body decays $B\to \varphi (\rho )K\gamma$ in perturbative QCD approach

    Chao Wang🇨🇳 · Jing-Bin Liu🇨🇳 · Hsiang-nan Li🇹🇼 · Cai-Dian Lü🇨🇳

    We study the three-body radiative decays $B\to \varphi (\rho )K\gamma$ induced by a flavor-changing neutral current in the perturbative QCD approach. Pseudoscalar-vector ($PV$) distribution amplitudes (DAs) are introduced for the final-state $\varphi K$ ($\rho K$) pair to capture important infrared dynamics in the region with a small $PV$-pair invariant mass. The dependence of these $PV$ DAs on the parton momentum fraction is parametrized in terms of the Gegenbauer polynomials, and the dependence on the meson momentum fraction is derived through their normalizations to time-like $PV$ form factors. In addition to the dominant electromagnetic penguin, the subleading chromomagnetic penguin, quark-loop and annihilation diagrams are also calculated. After determining the $PV$ DAs from relevant branching-ratio data, the direct $CP$ asymmetries and decay spectra in the $PV$-pair invariant mass are predicted for each $B\to \varphi (\rho )K\gamma$ mode.

    hep-phPRD(2018)·18 citations
26. 26*

    Extended Higgs-portal dark matter and the Fermi-LAT Galactic Center Excess

    J. A. Casas🇪🇸 · G. A. Gomez-Vargas🇨🇱 · J. M. Moreno🇪🇸 · J. Quilis🇪🇸 · R. Ruiz de Austri🇪🇸

    We show that the Galactic Center Excess (GCE) emission, as recently updated by the Fermi-LAT Collaboration, could be explained by the sum of Fermi-bubbles-like emission plus dark matter (DM) annihilation, in the context of a scalar-singlet Higgs portal scenario (SHP). In fact, the standard SHP, where the DM particle, $S$, only has renormalizable interactions with the Higgs, is non-operational due to strong constraints, specially from DM direct detection limits. Thus we consider a most economical extension, called ESHP (for extended SHP), which simply consists in the addition of a second (heavier) scalar singlet in the dark sector. The second scalar can be integrated-out, leaving a standard SHP plus a dimension-6 operator. Essentially, this model has only two relevant parameters (the DM mass and the coupling of the dim-6 operator). DM annihilation occurs mainly into two Higgs bosons, $SS\to hh$. We demonstrate that, despite its economy, the ESHP model provides excellent fits to the GCE (with p-value $\sim 0.6-0.7$) for very reasonable values of the parameters, in particular $m_S\simeq 130$ GeV. This is achieved without conflicting with other observables and keeping the $S-$particle relic density at the accepted value for the DM content in the universe.

    hep-phastro-ph.HEJCAP(2018)·4 citations
27. 27*

    6-quark Dark Matter

    Glennys R. Farrar🇺🇸

    It has recently been proposed that the relatively inert, highly symmetric, neutral flavor singlet scalar hadron made of uuddss quarks may have a mass < 2 (m_p + m_e). This is consistent with QCD theory, and with existing accelerator and non-accelerator constraints. For mass in the 1.5-1.8 GeV range, the observed DM relic abundance and the observed DM to ordinary matter ratio can emerge naturally. Dark matter freezes out before primordial nucleosynthesis and does not significantly impact primordial abundances, so the conventional argument that DM is non-baryonic does not apply. The interaction cross section between DM and the gas in the Galaxy is such that the dark matter in our local neighborhood is naturally co-rotating with the solar system, to a sufficient degree that DM may not have enough energy to be detected in applicable DM experiments. Interaction with the gas in galactic disks provides the first (non-MONDian) explanation for the striking correlation in the small-scale structure of rotation curves and the inhomogeneous distribution of gas, and also accounts (unlike MOND) for instances of galaxies not exhibiting such correlations. Depending on the cross-section, a DM-baryon interaction can produce a dark matter disk as suggested by recent studies, and has many or all virtues of self-interacting DM (SIDM) for removing inconsistencies of LCDM. Lab experiments to discover this particle are discussed.

    hep-phastro-ph.GAPoS(2018)·19 citations
28. 28*

    A model explaining neutrino masses and the DAMPE cosmic ray electron excess

    Yi-Zhong Fan🇨🇳 · Wei-Chih Huang🇩🇰 · Martin Spinrath🇹🇼 · Yue-Lin Sming Tsai🇹🇼 · Qiang Yuan🇨🇳

    We propose a flavored $U(1{)}_{e\mu }$ neutrino mass and dark matter~(DM) model to explain the recent DArk Matter Particle Explorer (DAMPE) data, which feature an excess on the cosmic ray electron plus positron flux around 1.4 TeV. Only the first two lepton generations of the Standard Model are charged under the new $U(1{)}_{e\mu }$ gauge symmetry. A vector-like fermion $\psi$, which is our DM candidate, annihilates into $e^{\pm }$ and ${\mu }^{\pm }$ via the new gauge boson $Z^{\prime }$ exchange and accounts for the DAMPE excess. We have found that the data favors a $\psi$ mass around 1.5~TeV and a $Z^{\prime }$ mass around 2.6~TeV, which can potentially be probed by the next generation lepton colliders and DM direct detection experiments.

    hep-phastro-ph.HEPLB(2018)·57 citations
29. 29*

    Electrophilic dark matter with dark photon: from DAMPE to direct detection

    Pei-Hong Gu🇨🇳 · Xiao-Gang He🇹🇼

    The electron-positron excess reported by the DAMPE collaboration recently may be explained by an electrophilic dark matter (DM). A standard model singlet fermion may play the role of such a DM when it is stablized by some symmetries, such as a dark $U(1{)}_X^{}$ gauge symmetry, and dominantly annihilates into the electron-positron pairs through the exchange of a scalar mediator. The model, with appropriate Yukawa couplings, can well interpret the DAMPE excess. Naively one expects that in this type of models the DM-nucleon cross section should be small since there is no tree-level DM-quark interactions. We however find that at one-loop level, a testable DM-nucleon cross section can be induced for providing ways to test the electrophilic model. We also find that a $U(1)$ kinetic mixing can generate a sizable DM-nucleon cross section although the $U(1{)}_X^{}$ dark photon only has a negligible contribution to the DM annihilation. Depending on the signs of the mixing parameter, the dark photon can enhance/reduce the one-loop induced DM-nucleon cross section.

    hep-phPLB(2018)·54 citations
30. 30*

    Radiative corrections to the ${\eta }^{(\prime )}$ Dalitz decays

    Tomas Husek🇨🇿 · Karol Kampf🇨🇿 · Stefan Leupold🇸🇪 · Jiri Novotny🇨🇿

    We provide the complete set of radiative corrections to the Dalitz decays ${\eta }^{(\prime )}\to {\ell }^{+}{\ell }^{-}\gamma$ beyond the soft-photon approximation, i.e. over the whole range of the Dalitz plot and with no restrictions on the energy of a radiative photon. The corrections inevitably depend on the ${\eta }^{(\prime )}\to {\gamma }^{\ast }{\gamma }^{(\ast )}$ transition form factors. For the singly virtual transition form factor appearing e.g. in the bremsstrahlung correction, recent dispersive calculations are used. For the one-photon-irreducible contribution at the one-loop level (for the doubly virtual form factor), we use a vector-meson-dominance-inspired model while taking into account the $\eta$-${\eta }^{\prime }$ mixing.

    hep-phhep-exPRD(2018)·19 citations
31. 31*

    Simplified TeV leptophilic dark matter in light of DAMPE data

    Guang Hua Duan🇨🇳 · Lei Feng🇨🇳 · Fei Wang🇨🇳 · Lei Wu🇨🇳 · Jin Min Yang🇨🇳 · Rui Zheng🇺🇸

    Using a simplified framework, we attempt to explain the recent DAMPE cosmic $e^{+}+e^{-}$ flux excess by leptophilic Dirac fermion dark matter (LDM). The scalar (${\Phi }_0$) and vector (${\Phi }_1$) mediator fields connecting LDM and Standard Model particles are discussed. Under constraints of DM relic density, gamma-rays, cosmic-rays and Cosmic Microwave Background (CMB), we find that the couplings $P\otimes S$, $P\otimes P$, $V\otimes A$ and $V\otimes V$ can produce the right bump in $e^{+}+e^{-}$ flux for a DM mass around 1.5 TeV with a natural thermal annihilation cross-section $<\sigma v>\sim 3\times 10^{-26}c{m}^3/s$ today. Among them, $V\otimes V$ coupling is tightly constrained by PandaX-II data (although LDM-nucleus scattering appears at one-loop level) and the surviving samples appear in the resonant region, $m_{{\Phi }_1}\simeq 2m_{\chi }$. We also study the related collider signatures, such as dilepton production $pp\to {\Phi }_1\to {\ell }^{+}{\ell }^{-}$, and muon $g-2$ anomaly. Finally, we present a possible $U(1{)}_X$ realization for such leptophilic dark matter.

    hep-phastro-ph.COJHEP(2018)·56 citations
32. 32*

    Probing SUSY effects in $K_S^0\to {\mu }^{+}{\mu }^{-}$

    Veronika Chobanova🇪🇸 · Giancarlo D'Ambrosio🇮🇹 · Teppei Kitahara🇩🇪 · Miriam Lucio Martinez🇪🇸 · Diego Martinez Santos🇪🇸 · Isabel Suarez Fernandez🇪🇸 · Kei Yamamoto🇯🇵

    We explore supersymmetric contributions to the decay $K_S^0\to {\mu }^{+}{\mu }^{-}$, in light of current experimental data. The Standard Model (SM) predicts $\mathcal{B}(K_S^0\to {\mu }^{+}{\mu }^{-})\approx 5\times 10^{-12}$. We find that contributions arising from flavour violating Higgs penguins can enhance the branching fraction up to $\approx 35\times 10^{-12}$ within different scenarios of the Minimal Supersymmetric Standard Model (MSSM), as well as suppress it down to $\approx 0.78\times 10^{-12}$. Regions with fine-tuned parameters can bring the branching fraction up to the current experimental upper bound, $8\times 10^{-10}$. The mass degeneracy of the heavy Higgs bosons in MSSM induces correlations between $\mathcal{B}(K_S^0\to {\mu }^{+}{\mu }^{-})$ and $\mathcal{B}(K_L^0\to {\mu }^{+}{\mu }^{-})$. Predictions for the $CP$ asymmetry in $K^0\to {\mu }^{+}{\mu }^{-}$ decays in the context of MSSM are also given, and can be up to eight times bigger than in the SM.

    hep-phJHEP(2018)·64 citations
33. 33*

    Freezing In, Heating Up, and Freezing Out: Predictive Nonthermal Dark Matter and Low-Mass Direct Detection

    Gordan Krnjaic🇺🇸

    Freeze-in dark matter (DM) mediated by a light ($\ll$ keV) weakly-coupled dark-photon is an important benchmark for the emerging low-mass direct detection program. Since this is one of the only predictive, detectable freeze-in models, we investigate how robustly such testability extends to other scenarios. For concreteness, we perform a detailed study of models in which DM couples to a light scalar mediator and acquires a freeze-in abundance through Higgs-mediator mixing. Unlike dark-photons, whose thermal properties weaken stellar cooling bounds, the scalar coupling to Standard Model (SM) particles is subject to strong astrophysical constraints, which severely limit the fraction of DM that can be produced via freeze-in. While it seems naively possible to compensate for this reduction by increasing the mediator-DM coupling, sufficiently large values eventually thermalize the dark sector with itself and yield efficient DM annihilation to mediators, which depletes the freeze-in population; only a small window of DM candidate masses near the $\sim$ GeV scale can accommodate the total observed abundance. Since many qualitatively similar issues arise for other light mediators, we find it generically difficult to realize a viable freeze-in scenario in which production arises only from renormalizable interactions with SM particles. We also comment on several model variations that may evade these conclusions.

    hep-phJHEP(2018)·38 citations
34. 34*

    Asymptotically Free Natural SUSY Twin Higgs

    Marcin Badziak🇵🇱 · Keisuke Harigaya🇺🇸

    Twin Higgs (TH) models explain the absence of new colored particles responsible for natural electroweak symmetry breaking (EWSB). All known ultraviolet completions of TH models require some non-perturbative dynamics below the Planck scale. We propose a supersymmetric model in which the TH mechanism is introduced by a new asymptotically free gauge interaction. The model features natural EWSB for squarks and gluino heavier than 2 TeV even if supersymmetry breaking is mediated around the Planck scale, and has interesting flavor phenomenology including the top quark decay into the Higgs and the up quark which may be discovered at the LHC.

    hep-phPRL(2018)·49 citations
35. 35*

    Telescoping jet substructure

    Yang-Ting Chien🇺🇸 · Alex Emerman🇺🇸 · Shih-Chieh Hsu🇺🇸 · Samuel Meehan🇺🇸 · Zachery Montague🇺🇸

    We introduce a novel jet substructure method which exploits the variation of observables with respect to a sampling of phase-space boundaries quantified by the variability. We apply this technique to identify boosted W boson and top quark jets using telescoping subjets which utilizes information coming from subjet topology and that coming from subjet substructure. We find excellent performance of the variability, in particular its robustness against finite detector resolution. The extension to telescoping jet grooming and other telescoping jet substructure observables is also straightforward. This method provides a new direction in heavy particle tagging and suggests a systematic approach to the decomposition of jet substructure.

    hep-phhep-exnucl-exPRD(2020)·10 citations
36. 36*

    Primordial magnetic field generation in the Quark Gluon Plasma phase

    Abhishek Atreya🇮🇳 · Soma Sanyal🇮🇳

    In this work we investigate the possibility of generation of primordial magnetic field in the early universe near the QCD phase transition epoch via the collapse of $Z(3)$ domains. The $Z(3)$ domain walls arise in the deconfined phase of the QCD (above $T\sim 200$ MeV) and their collapse leads to a net quark concentration near the wall boundary due to non-trivial reflection of quarks. We look at the response of leptons to this quark excess and find that leptons do not cancel the electric charge concentration due to the quarks. The wall collapse and a net charge concentration can lead to the generation of vorticity and turbulence in the primordial plasma. We estimate the magnitude of the magnetic field generated and find that it can be quite large $\mathcal{O}(10^{15-18}\mathrm{G})$. The mechanism is independent of the order of the QCD phase transition.

    hep-phastro-ph.COhep-thEPJC(2018)·3 citations
37. 37*

    Non-thermal Production of Dark Matter from Primordial Black Holes

    Rouzbeh Allahverdi🇺🇸 · James B. Dent🇺🇸 · Jacek Osinski🇺🇸

    We present a scenario for non-thermal production of dark matter from evaporation of primordial black holes. A period of very early matter domination leads to formation of black holes with a maximum mass of $\simeq 2\times 10^8$ g, whose subsequent evaporation prior to big bang nucleosynthesis can produce all of the dark matter in the universe. We show that the correct relic abundance can be obtained in this way for thermally underproduced dark matter in the 100 GeV-10 TeV mass range. To achieve this, the scalar power spectrum at small scales relevant for black hole formation should be enhanced by a factor of $\mathcal{O}(10^5)$ relative to the scales accessible by the cosmic microwave background experiments.

    ↳ astro-ph.COhep-phhep-thPRD(2018)·110 citations
38. 38*

    Initial state and hydrodynamic modeling of heavy-ion collisions at RHIC BES energies

    Chun Shen🇺🇸 · Björn Schenke🇺🇸

    We present a fully three-dimensional initial state model for relativistic heavy-ion collisions at RHIC Beam Energy Scan (BES) collision energies. The initial energy and net baryon density profiles are produced based on a classical string deceleration model. The baryon stopping and fluctuations during this early stage of the collision are investigated by studying the net baryon rapidity distribution and longitudinal decorrelation of the transverse geometry.

    ↳ nucl-thhep-phnucl-exPoS(2018)·19 citations
39. 39*

    Critical behavior of gauge theories and Coulomb gases in three and four dimensions

    Aleksey Cherman🇺🇸 · Mithat Unsal🇺🇸

    Gauge theories with matter often have critical regions in their parameter space where gapless degrees of freedom emerge. Using controlled semiclassical calculations, we explore such critical regions in $SU(N)$ gauge theories with a topological $\theta$ term and $N_F$ fundamental fermions in four dimensions, as well as related field theories in three dimensions. In four-dimensional theories, we find that for all $N_F\ge 1$ the critical behavior always occurs at a point in parameter space. For $N_F>1$ this is consistent with the standard QCD expectations, while for $N_F=1$ our results are consistent with recent observations concerning 't Hooft anomalies. We also show how the $N$-branched structure of observables transmutes into the $N_F$-branched structure seen in chiral Lagrangians as the mass parameter is dialed. As a side benefit, our analysis of these 4D theories implies the unexpected result that 3D Coulomb gases can have gapless critical points. We also consider QCD-like parity-invariant theories in three dimensions, and find that their critical behavior is quite different. In particular, we show that their gapless region is an interval in parameter space, rather than a point. Our results have non-trivial implications for the infrared behavior of three-dimensional compact QED.

    ↳ hep-thhep-ph24 citations
40. 40*

    Intro to Effective Field Theories and Inflation

    C.P. Burgess🇨🇦

    These notes present an introduction to $\Lambda$CDM cosmology and its possible inflationary precursor, with an emphasis on some of the ways effective field theories are used in its analysis. The intended audience are graduate students in particle physics, such as attended the lectures (prepared for the Les Houches Summer School, Effective Field Theory in Particle Physics and Cosmology, July 2017).

    ↳ hep-thastro-ph.COgr-qchep-ph42 citations
41. 41*

    Hadrons in Nuclei

    Laura Tolos🇩🇪

    A review on the state-of-the-art of heavy hadrons in nuclei is presented. In particular, the properties of mesons with strangeness and charm in matter are discussed, paying a special attention to the formation of exotic bound states in nuclei.

    ↳ nucl-thhep-exhep-phPoS(2018)·0 citations
42. 42*

    Toward a QFT treatment of nonexponential decay

    Francesco Giacosa🇩🇪

    We study the properties of the survival probability of an unstable quantum state described by a Lee Hamiltonian. This theoretical approach resembles closely Quantum Field Theory (QFT): one can introduce in a rather simple framework the concept of propagator and Feynman rules, Within this context, we re-derive (in a detailed and didactical way) the well-known result according to which the amplitude of the survival probability is the Fourier transform of the energy distribution (or spectral function) of the unstable state (in turn, the energy distribution is proportional to the imaginary part of the propagator of the unstable state). Typically, the survival probability amplitude is the starting point of many studies of non-exponential decays. This work represents a further step toward the evaluation of the survival probability amplitude in genuine relativistic QFT. However, although many similarities exist, QFT presents some differences w.r.t. the Lee Hamiltonian which should be studied in the future.

    ↳ hep-thhep-phquant-phEPJ Web Conf.(2018)·1 citation
43. 43*

    Accelerating hydrodynamic description of pseudorapidity density and the initial energy density in p+p, Cu+Cu, Au+Au, and Pb+Pb collisions at RHIC and LHC

    Jiang Ze-Fang🇨🇳 · Yang Chun-Bin🇨🇳 · Mate Csanad🇭🇺 · Tamas Csorgo🇭🇺

    A known class of analytic, exact, accelerating solutions of prefect relativistic hydrodynamics with longitudinal acceleration is utilized to describe results on the pseudorapidity distributions for different collision systems. These results include $dN/d\eta$ measured in p+p, Cu+Cu, Au+Au, and Pb+Pb collisions at RHIC and LHC, in a broad centrality range. Going beyond the traditional Bjorken model, from the accelerating hydrodynamic description we determine the initial energy density and other thermodynamic quantities in those collisions.

    ↳ nucl-thhep-phPRC(2018)·20 citations
44. 44*

    A Two-point Diagnostic for the HII Galaxy Hubble Diagram

    Kyle Leaf🇺🇸 · Fulvio Melia🇺🇸

    A previous analysis of starburst-dominated HII Galaxies and HII regions has demonstrated a statistically significant preference for the Friedmann-Robertson-Walker cosmology with zero active mass, known as the R_h=ct universe, over LCDM and its related dark-matter parametrizations. In this paper, we employ a 2-point diagnostic with these data to present a complementary statistical comparison of R_h=ct with Planck LCDM. Our 2-point diagnostic compares---in a pairwise fashion---the difference between the distance modulus measured at two redshifts with that predicted by each cosmology. Our results support the conclusion drawn by a previous comparative analysis demonstrating that R_h=ct is statistically preferred over Planck LCDM. But we also find that the reported errors in the HII measurements may not be purely Gaussian, perhaps due to a partial contamination by non-Gaussian systematic effects. The use of HII Galaxies and HII regions as standard candles may be improved even further with a better handling of the systematics in these sources.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phMNRAS(2018)·11 citations
45. 45*

    Resumming perturbative series in the presence of monopole bubbling effects

    Masazumi Honda🇮🇱 · Daisuke Yokoyama🇬🇧

    Monopole bubbling effect is screening of magnetic charges of singular Dirac monopoles by regular 't Hooft-Polyakov monopoles. We study properties of weak coupling perturbative series in the presence of monopole bubbling effects as well as instantons. For this purpose, we analyze supersymmetric 't Hooft loop in four dimensional $\mathcal{N}=2$ supersymmetric gauge theories with Lagrangians and non-positive beta functions. We show that the perturbative series of the 't Hooft loop is Borel summable along positive real axis for fixed instanton numbers and screened magnetic charges. It turns out that the exact result of the 't Hooft loop is the same as the sum of the Borel resummations over instanton numbers and effective magnetic charges. We also obtain the same result for supersymmetric dyonic loops.

    ↳ hep-thcond-mat.str-elhep-phmath-ph+1PRD(2019)·14 citations
46. 46*

    Study of double parton scattering processes with heavy quarks

    Ivan Belyaev🇷🇺 · Daria Savrina🇷🇺

    Study of double parton scattering processes (DPS) involving heavy quarks provides the most precise probing of factorization hypothesis for DPS for gluon-mediated processes. The measurements are performed for the different final states, including open and hidden-flavour hadrons and for the different kinematic ranges of incoming gluons

    ↳ hep-exhep-phAdv.Ser.Direct.High Energy Phys.(2018)·14 citations
47. 47*

    Direct detection of a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons

    G. Ambrosi🇮🇹 · Q. An🇨🇳 · R. Asfandiyarov🇨🇭 · P. Azzarello🇨🇭 · P. Bernardini🇮🇹 · B. Bertucci🇮🇹 · M. S. Cai🇨🇳 · J. Chang🇨🇳 · D. Y. Chen🇨🇳 · H. F. Chen🇨🇳 · J. L. Chen🇨🇳 · W. Chen🇨🇳 and 146 other authors

    High energy cosmic ray electrons plus positrons (CREs), which lose energy quickly during their propagation, provide an ideal probe of Galactic high-energy processes and may enable the observation of phenomena such as dark-matter particle annihilation or decay. The CRE spectrum has been directly measured up to $\sim 2$ TeV in previous balloon- or space-borne experiments, and indirectly up to $\sim 5$ TeV by ground-based Cherenkov $\gamma$-ray telescope arrays. Evidence for a spectral break in the TeV energy range has been provided by indirect measurements of H.E.S.S., although the results were qualified by sizeable systematic uncertainties. Here we report a direct measurement of CREs in the energy range $25\mathrm{GeV}-4.6\mathrm{TeV}$ by the DArk Matter Particle Explorer (DAMPE) with unprecedentedly high energy resolution and low background. The majority of the spectrum can be properly fitted by a smoothly broken power-law model rather than a single power-law model. The direct detection of a spectral break at $E\sim 0.9$ TeV confirms the evidence found by H.E.S.S., clarifies the behavior of the CRE spectrum at energies above 1 TeV and sheds light on the physical origin of the sub-TeV CREs.

    ↳ astro-ph.HEhep-exhep-phNature(2017)·608 citations
48. 48*

    Interpretations of the DAMPE electron data

    Qiang Yuan🇨🇳 · Lei Feng🇨🇳 · Peng-Fei Yin🇨🇳 · Yi-Zhong Fan🇨🇳 · Xiao-Jun Bi🇨🇳 · Ming-Yang Cui🇨🇳 · Tie-Kuang Dong🇨🇳 · Yi-Qing Guo🇨🇳 · Kun Fang🇨🇳 · Hong-Bo Hu🇨🇳 · Xiaoyuan Huang🇩🇰 · Shi-Jun Lei🇨🇳 and 17 other authors

    The DArk Matter Particle Explorer (DAMPE), a high energy cosmic ray and $\gamma$-ray detector in space, has recently reported the new measurement of the total electron plus positron flux between 25 GeV and 4.6 TeV. A spectral softening at $\sim 0.9$ TeV and a tentative peak at $\sim 1.4$ TeV have been reported. We study the physical implications of the DAMPE data in this work. The presence of the spectral break significantly tightens the constraints on the model parameters to explain the electron/positron excesses. The spectral softening can either be explained by the maximum acceleration limits of electrons by astrophysical sources, or a breakdown of the common assumption of continuous distribution of electron sources at TeV energies in space and time. The tentive peak at $\sim 1.4$ TeV implies local sources of electrons/positrons with quasi-monochromatic injection spectrum. We find that the cold, ultra-relativistic $e^{+}{e}^{-}$ winds from pulsars may give rise to such a structure. The pulsar is requird to be middle-aged, relatively slowly-rotated, mildly magnetized, and isolated in a density cavity. The annihilation of DM particles ($m_{\chi }\sim 1.5$ TeV) into $e^{+}{e}^{-}$ pairs in a nearby clump or an over-density region may also explain the data. In the DM scenario, the inferred clump mass (or density enhancement) is about $10^7-10^8$ M${}_{\odot }$ (or $17-35$ times of the canonical local density) assuming a thermal production cross section, which is relatively extreme compared with the expectation from numerical simulations. A moderate enhancement of the annihilation cross section via, e.g., the Sommerfeld mechanism or non-thermal production, is thus needed.

    ↳ astro-ph.HEhep-ph93 citations
49. 49*

    Explanation of the knee-like feature in the DAMPE cosmic $e^{-}+e^{+}$ energy spectrum

    Kun Fang🇨🇳 · Xiao-Jun Bi🇨🇳 · Peng-Fei Yin🇨🇳

    The DArk Matter Particle Explorer (DAMPE), a space-based high precision cosmic ray detector, has just reported the new measurement of the total electron plus positron energy spectrum up to 4.6 TeV. A notable feature in the spectrum is the spectral break at $\sim 0.9$ TeV, with the spectral index softening from $-3.1$ to $-3.9$. Such a feature is very similar to the knee at the cosmic nuclei energy spectrum. In this work we propose that the knee-like feature can be explained naturally by assuming that the electrons are accelerated at the supernova remnants (SNRs) and released when the SNRs die out with lifetime around $10^5$ years. The cut-off energy of those electrons have already decreased to several TeV due to radiative cooling, which may induce the observed TeV spectral break. Another possibility is that the break is induced by a single nearby old SNR. Such a scenario may bring a large electron flux anisotropy that is observable by the future detectors. We also show that a minor part of electrons escaping during the acceleration in young and nearby SNRs are able to contribute to several TeV or higher energy region of the spectrum.

    ↳ astro-ph.HEhep-phApJ(2018)·60 citations
50. 50*

    Lattice QCD calculation of the $B_{(s)}\to D_{(s)}^{\ast }\ell \nu$ form factors at zero recoil and implications for $|V_{cb}|$

    Judd Harrison🇬🇧 · Christine Davies🇬🇧 · Matthew Wingate🇬🇧

    We present results of a lattice QCD calculation of $B\to D^{\ast }$ and $B_s\to D_s^{\ast }$ axial vector matrix elements with both states at rest. These zero recoil matrix elements provide the normalization necessary to infer a value for the CKM matrix element $|V_{cb}|$ from experimental measurements of ${\bar{B}}^0\to D^{\ast +}{\ell }^{-}\bar{\nu }$ and ${\bar{B}}_s^0\to D_s^{\ast +}{\ell }^{-}\bar{\nu }$ decay. Results are derived from correlation functions computed with highly improved staggered quarks (HISQ) for light, strange, and charm quark propagators, and nonrelativistic QCD for the bottom quark propagator. The calculation of correlation functions employs MILC Collaboration ensembles over a range of three lattice spacings. These gauge field configurations include sea quark effects of charm, strange, and equal-mass up and down quarks. We use ensembles with physically light up and down quarks, as well as heavier values. Our main results are ${\mathcal{F}}^{B\to D^{\ast }}(1)=0.895\pm 0.010_{\mathrm{stat}}\pm {0.024}_{\mathrm{sys}}$ and ${\mathcal{F}}^{B_s\to D_s^{\ast }}(1)=0.883\pm 0.010_{\mathrm{stat}}\pm 0.028_{\mathrm{sys}}$. We discuss the consequences for $|V_{cb}|$ in light of recent investigations into the extrapolation of experimental data to zero recoil.

    ↳ hep-lathep-phPRD(2018)·107 citations
51. 51*

    Extracting the Energy-Dependent Neutrino-Nucleon Cross Section Above 10 TeV Using IceCube Showers

    Mauricio Bustamante🇩🇰 · Amy Connolly🇺🇸

    Neutrinos are key to probing the deep structure of matter and the high-energy Universe. Yet, until recently, their interactions had only been measured at laboratory energies up to about 350 GeV. An opportunity to measure their interactions at higher energies opened up with the detection of high-energy neutrinos in IceCube, partially of astrophysical origin. Scattering off matter inside the Earth affects the distribution of their arrival directions --- from this, we extract the neutrino-nucleon cross section at energies from 18 TeV to 2 PeV, in four energy bins, in spite of uncertainties in the neutrino flux. Using six years of public IceCube High-Energy Starting Events, we explicitly show for the first time that the energy dependence of the cross section above 18 TeV agrees with the predicted softer-than-linear dependence, and reaffirm the absence of new physics that would make the cross section rise sharply, up to a center-of-mass energy of ~1 TeV.

    ↳ astro-ph.HEhep-exhep-phPRL(2019)·151 citations
52. 52*

    Pre-ADS Superpotential from Confined Monopoles

    Csaba Csáki🇺🇸 · Mario Martone🇺🇸 · Yuri Shirman🇺🇸 · John Terning🇺🇸

    According to the standard lore only single monopoles contribute to the superpotential on the Coulomb branch of 3D $\mathcal{N}=2$ SUSY gauge theories. However we argue that multi-monopole configurations can also generate superpotential terms in the presence of squark VEVs on the mixed Higgs-Coulomb branch. The new ingredient is the confinement of monopoles via Nielsen-Olesen flux tubes. Such confined multi-monopoles will yield a pre-ADS superpotential which depends both on the local Coulomb moduli and matter superfields but has no fractional powers. Once the lifted moduli are integrated out the familiar ADS superpotential is obtained. Our results demonstrate the important role multi-monopoles can play in generating non-perturbative effects and also sheds light on the still somewhat mysterious dynamical origin of the general 4D ADS superpotential.

    ↳ hep-thhep-phJHEP(2018)·8 citations
53. 53*

    From $R^2$ Gravity to No-Scale Supergravity

    John Ellis🇬🇧 · Dimitri V. Nanopoulos🇺🇸 · Keith A. Olive🇺🇸

    We show that $R^2$ gravity coupled conformally to scalar fields is equivalent to the real bosonic sector of SU(N,1)/SU(N)$\times$U(1) no-scale supergravity, where the conformal factor can be identified with the Kähler potential, and we review the construction of Starobinsky-like models of inflation within this framework.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2018)·30 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.